I have a mac and I am trying to install UE4 but this window pops up and tells me UE4 quit unexpectedly. What should I do?
This window is the one that shows up.
You need to upgrade your mac OS to version 10.10.5 or higher as it states. Your OS is version 10.9.5.
I am having a simular problem. I’m using macincloud to build my ios version of my game. the server is on Mac OS X 10.11.4, 8 gig of ram, and I believe twin dual-core processors.
Try the steps in this thread, the column where it says mach_msg_trap +10 one of those is indicating were the exception occurred so hit the apple forum and you will get it answered.
EXC_CRASH (SIGABRT) implies that you crashed because something aborted.
The process exited abnormally. The most common cause of crashes with this exception type are uncaught Objective-C/C++ exceptions.
https://developer.apple.com/library/ios/technotes/tn2151/_index.html
Javelin69 doesn’t meet the system requirements so they’re not really similar and I’ll never own a mac 
This sucks, because it worked perfectly before for me. When I launched this morning, it said there is an update, would I like to do it? When I said yes, it deleted my working version with the version that only works on 10.10!!! Now I can’t even use it! Why offer a download from within the app, and it doesn’t recognize my operating system! How can I down-grade back to a working version???
Hi everyone,
I’m sorry that you are having an issue with the Epic Games Launcher. In order for us to offer the best support, we have recently modified the process for how Epic Games can help troubleshoot your Launcher issue. Please visit http://help.epicgames.com/ for technical support, here you can find information and solutions for common issues, as well as a contact form if you still need additional assistance. Thanks!
The error specifically says Javelin69’s OS is not supported.
"application requires at least Mac OS X version 10.10.5 (10.10.5), but is being run on 10.9.5 (10.9.5/13F1712), and so is exiting."
The problem is that I simply launched “Epic Games Launcher”, and it said there is a new version available. This type of message is just like every other game or application available to mankind. The difference is, Epic failed to mention “There is a new version available, would you like to download AS LONG AS YOU UPGRADE 2 VERSIONS NEWER OF THE OPERATING SYSTEM YOU ARE RUNNING.” I think offering to upgrade their software, and telling people AFTER THE FACT that, “OOOPS, you are no longer going to be able to use this program! Go try Unity instead, sucker!”